• 제목/요약/키워드: Cell size

검색결과 3,853건 처리시간 0.03초

Effects of Silicone Surfactant on the Cell Size and Thermal Conductivity of Rigid Polyurethane Foams by Environmentally Friendly Blowing Agents

  • Han, Mi-Sun;Choi, Seok-Jin;Kim, Ji-Mun;Kim, Youn-Hee;Kim, Woo-Nyon;Lee, Heon-Sang;Sung, Joon-Yong
    • Macromolecular Research
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    • 제17권1호
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    • pp.44-50
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    • 2009
  • Rigid polyurethane foams (PUF)s were synthesized with environmentally friendly blowing agents such as a cyclopentane/distilled water (10.0/1.0, pphp) mixture and distilled water only for four different silicone surfactants having different silicone/polyether ratios. An attempt was made to reduce the thermal conductivities of the PUF samples by varying the concentration and the silicone/polyether ratio of the various silicone surfactants. The scanning electron microscopy (SEM) results indicated an optimum concentration of the silicone surfactant of about 1.5 to 2.5 phpp for various surfactants to reduce the cell size and lower the thermal conductivity. The silicone surfactant having a higher silicone/polymer ratio showed a smaller cell size and, therefore, demonstrated the lower thermal conductivity of the PUF samples. From the relation between the thermal conductivity and the cell size of the PUF samples, the smaller cell size improved the thermal insulation property of the rigid PUF for both the PUF samples blown by the cyclopentane/distilled water (10.0/1.0, pphp) mixture and distilled water only. If the blowing agent is fixed, then the cell size is an important factor to decrease the thermal conductivity of the PUF samples. These results indicated that rigid PUF samples having lower thermal conductivity can be obtained by choosing a silicone surfactant containing a higher silicone/polyether ratio, as well as an optimum content of the surfactant.

배지종류, 셀크기 및 비료종류가 호접란 플러그묘 생장에 미치는 영향 (Effects of Media, Cell Sizes and Fertilizers on the Growth of Phalaenopsis Plug Plants)

  • 정용모;빈철구;김진기;진영돈;정순재;권오창
    • 생명과학회지
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    • 제9권6호
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    • pp.665-670
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    • 1999
  • The effects of media, cell sizes and fertilizers on the early growth of Phalaenopsis plug plants were investigate. The sphagnum moss was more effective than other media in pink and white color cultivars. In comparison of different plug cell size, 50 cell size was more effective then 72 and 128 cell size in pink and white cultivar. In comparison of different fertilizer, margamf K in pink, and nutrient solution II(one time drenching with NHRI standard solution for three times irrigation) in white color cultivars was more effective then others, respectively.

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전위쎌에 기초한 미세조직 구성모델을 이용한 ECAP 공정 시 변형과 미세조직의 진화 해석 (Analysis of Deformation and Microstructural Evolution during ECAP Using a Dislocation Cell Related Microstructure-Based Constitutive Model)

  • 김형섭
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 추계학술대회논문집
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    • pp.207-210
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    • 2004
  • The deformation behavior of copper during equal channel angular pressing (ECAP) was calculated using a three-dimensional version of a constitutive model based on the dislocation density evolution. Finite element simulations of the variation of the dislocation density and the dislocation cell size with the number of ECAP passes are reported. The calculated stress, strain and cell size are compared with the experimental data for Cu deformed by ECAP in a modified Route C regime. The results of FEM analysis were found to be in good agreement with the experiments. After a rapid initial decrease down to about 200 nm in the first ECAP pass, the average cell size was found to change little with further passes. Similarly, the strength increased steeply after the first pass, but tended to saturate with further pressings. The FEM simulations also showed strain non-uniformities and the dependence of the resulting strength on the location within the workpiece.

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Daucus carota 현탁 배양에서 배지 조성 및 세포 응집 크기가 Carotenoid 생합성에 미치는 영향 (Effects of Nutrients and Cell Aggregate Size on the Biosynthesis of Carotenoid in Daucus carota Suspension Culture)

  • 윤정원;김지현유영제변상요
    • KSBB Journal
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    • 제5권4호
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    • pp.347-353
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    • 1990
  • The effects of nutrients and cell aggregate size on the cell growth of D. carota and the biosynthesi of carotenoid were investigated. Highest carotenoid content was obtained with sucrose as a carbon source and the equal ratio of ammonium to nitrate. High phosphate concentration stimulated the carotenoid biosynthesis in D. corota. 2,4-D inhibited the cell growth but stimulated the specific carotenoid content at high concentration. By modifying the medium composition based on these findings, three times higher specific carotenoid content and 2.5 times higher total carotenoid content were obtained as compared with the results obtained with basic MS media. Biosynthesis of carotenoid was found to be affected by cell aggregate size; high carotenoid production was obtained from the large aggregated cells resulted from high sucrose concentration.

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Control the crystal size by varying concentrations of precursors for the planar perovskite solar cells

  • Xie, Lin;Hwang, Heewon;Kim, Minjung;Kim, Kyungkon
    • Rapid Communication in Photoscience
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    • 제4권4호
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    • pp.79-81
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    • 2015
  • The influence of the grain size of the $CH_3NH_3PbI_3$ on the solar cell performance is investigated by controlling the ratio between $CH_3NH_3I$ and $PbI_2$ precursors. As the concentration of the precursors increased from 1.0M to 2.0M, the $CH_3NH_3PbI_3$ grain size increased from ~100nm to ~400nm. The solar cell utilizing the $CH_3NH_3PbI_3$ with large grain size shows improved photocurrent compared to the solar cell utilizing $CH_3NH_3PbI_3$ with small grain size, which is ascribed to the reduced recombination at the boundaries of grains.

팔정산가감방(八正散加減方)이 고지방식이(高脂肪食餌)를 한 백서(白鼠)의 간(肝) 및 부고환지방조직(副睾丸脂肪組織)에 미치는 영향(影響)에 대한 조직화학적(組織化學的) 연구(硏究) (The Histological Study about the Effects of Paljeungsan-gagambang on Liver and Epididymal Cell of Rats Fed High Fat Diet)

  • 김봉현;김상찬;김선희;김연변
    • 대한한의학방제학회지
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    • 제6권1호
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    • pp.141-156
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    • 1998
  • This histological study was performed to investigate the effects of .Paljeungsan-gagambang on the epididymal fat cell size, number and the fat drop area of hepatic lobule of rats fed High Fat Diet. Paljeungsan-gagambang was orally administered to the rats of sample group 26mg per 200g of rat's weight everyday for 4 weeks, and the control group were just fed with equal amount of saline solution. Then they are the epididymal fat cell size, epididymal fat cell numberand fat drop area of hepatic lobule that were measured. The results were summarized as follows; 1. The size of the epididymal fat cell was decreased significantly as compared with the control group. 2. The number of the epididymal fat cells was decreased significantly as compared with the control group in distribution chart classified by cell size 3. The Area(%) of the Fat drops in the hepatic lobule was decreased significantly as compared with the control group. According to the above results, it is considered that Paljeungsan-gagambang have effects on the decrease of the epididymal fat cell size, number and fat drop area of hepatic lobule of rats fed high fat diet; Thus, the adminisrtation of Paljeungsan-gagambang is considered to have an improving effect on obesities and liver diseases caused by high fat diet.

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분산형 비점오염원 모델에서 단위유역 크기의 민감도 분석 (A Sensitivity Analysis of Cell Size on a Distributed Non-Point Source Pollution Model)

  • 배인희;박정은;박석순
    • 대한환경공학회지
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    • 제27권9호
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    • pp.952-957
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    • 2005
  • 분산형 비점오염원 모델에서 단위유역 크기의 영향을 검토하기 위하여 민감도 분석 연구를 실시하였다. 미농무성의 AGNPS 모델에서 변형된 AnnAGNPS 모델을 남한강 수계의 청미천의 지류인 응천 유역에 적용하였다. 10에서 200 헥타르에 이르는 다양한 단위유역 크기에 따라 유로연장, 경사, 토지 이용, 유달율 등과 같은 모델 요소와 결과를 분석하였다. 단위유역의 크기가 증가함에 따라 휘어진 하천이 단거리로 계산되기 때문에 유로연장이 감소하게 되고, 이것은 다른 어떤 지형 변화보다 모델 결과에 중요한 영향을 미치는 것으로 나타났다. 토지 이용도와 토양 분포 효과가 제외되었을 경우, 단위유역이 클수록 유역의 최종유출구까지 도달하는 시간이 짧아져 토사 유달 부하량이 증가하였다. 그러나 이러한 영향이 포함되었을 경우, 단위유역이 클수록 적용 유역의 토지이용의 다양도가 포함될 수 없기 때문에 토사 유달 부하량이 감소하였다. 적용 유역은 토양 침식이 낮은 임야로 이루어져 단위유역이 큰 경우에는 임야 비율이 더욱 증가하여 유달 부하량이 감소하게 된 것이다. 적용 유역에서는 30 헥타르의 단위 유역이 가장 적합한 크기로 결정되었다. 강우 유출수량과 총질소, 총인, 생물화학적 산소요구량을 모델에서 예측하였으며 현장 측정치와 적절히 일치하였다. 본 연구를 통하여 모델 결과는 단위유역 크기에 따라 변하는 지형, 토지 이용, 토양분포 변이에 민감하게 변하며, 성공적인 분산형 모델적용을 위하여 최적의 단위유역 크기를 사용하는 것이 매우 중요하다는 결론을 얻었다.

쥐의 초기 난포 발달에 관여하는 Cell Size Growth 및 CCN Family 유전자에 관한 연구 (Characterization of Genes Related to the Cell Size Growth and CCN Family According to the Early Folliculogenesis in the Mouse)

  • 김경화;박창은;윤세진;이경아
    • Clinical and Experimental Reproductive Medicine
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    • 제32권3호
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    • pp.269-277
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    • 2005
  • Objectives: Previously, we sought to compile a list of genes expressed during early folliculogenesis by using cDNA microarray to investigate follicular gene expression and changes during primordialprimary follicle transition and development of secondary follicles (Yoon et al., 2005). Among those genes, a group of genes related to the cell size growth was characterized during the ovarian development in the present study. Methods: We determined ovarian expression pattern of six genes related to the cell size growth (cyr61, emp1, fhl1, socs2, wig1 and wisp1) and extended into CCN family (${\underline{c}}onnective$ tissue growth factor/${\underline{c}}ysteine$-rich 61/${\underline{n}}ephroblastoma$-overexpressed), ctgf, nov, wisp2, wisp3, including cyr61 and wisp1 genes. Expression of mRNA and protein according to the ovarian developmental stage was evaluated by in situ hybridization, and/or semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and immunohistochemistry, respectively. Results: Among 6 genes related to the cell size growth, cyr61 and wisp1 mRNA was detected only in oocytes in the postnatal day5 mouse ovaries. cyr61 mRNA expression was limited to the nucleolus of oocytes, while wisp1 was expressed in the cytoplasm and nucleolus of oocytes, except nucleus. cyr61 mRNA expression, however, was found in granulosa cells from secondary follicles. The rest 4 genes in the cell size growth group were detected in oocytes, granulosa and theca cells. Cyr61 and Wisp1 proteins were expressed in the oocyte cytoplasm from primordial follicle stage. Especially, Cyr61 protein was detected in pre-granulosa cells, Wisp1 protein was not. By using RT-PCR, we evaluated and decided that Cyr61 protein is produced by their own mRNA in pre-granulosa cells that was not detected by in situ hybridization. cyr61 and wisp1 genes are happen to be the CCN family members. The other members of CCN family were also studied, but their expression was detected in oocytes, granulose and theca cells. Conclusions: We firstly characterized the ovarian expression of genes related to the cell size growth and CCN family according to the early folliculogenesis. Cyr61 protein expression in the pre-granulosa cells is profound in meaning. Further functional analysis for cyr61 in early folliculogenesis is under investigation.

Overexpression of the Downward Leaf Curling (DLC) Gene from Melon Changes Leaf Morphology by Controlling Cell Size and Shape in Arabidopsis Leaves

  • Kee, Jae-Jun;Jun, Sang Eun;Baek, Seung-A;Lee, Tae-Soo;Cho, Myung Rae;Hwang, Hyun-Sik;Lee, Suk-Chan;Kim, Jongkee;Kim, Gyung-Tae;Im, Kyung-Hoan
    • Molecules and Cells
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    • 제28권2호
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    • pp.93-98
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    • 2009
  • A plant-specific gene was cloned from melon fruit. This gene was named downward leaf curling (CmDLC) based on the phenotype of transgenic Arabidopsis plants overexpressing the gene. This expression level of this gene was especially upregulated during melon fruit enlargement. Overexpression of CmDLC in Arabidopsis resulted in dwarfism and narrow, epinastically curled leaves. These phenotypes were found to be caused by a reduction in cell number and cell size on the adaxial and abaxial sides of the epidermis, with a greater reduction on the abaxial side of the leaves. These phenotypic characteristics, combined with the more wavy morphology of epidermal cells in overexpression lines, indicate that CmDLC overexpression affects cell elongation and cell morphology. To investigate intracellular protein localization, a CmDLC-GFP fusion protein was made and expressed in onion epidermal cells. This protein was observed to be preferentially localized close to the cell membrane. Thus, we report here a new plant-specific gene that is localized to the cell membrane and that controls leaf cell number, size and morphology.

Wax Gourd Reduces Adipose Depots and Fat Cell Sizes without Affecting the Levels of Leptin in Rats Fed Medium Fat

  • Kang Keum-Jee
    • Nutritional Sciences
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    • 제9권3호
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    • pp.173-178
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    • 2006
  • The purpose of this study was to investigate the effects of wax gourd on body weight, body fat, triglyceride, leptin and fat cell size in rats fed medium fat Male Sprague Dawley rats were fed with experimental diet containing total dietary fat at 20% of calorie with wax gourd (WG) for 4 weeks. Forty rats were divided into 4 groups including control, 5, 10, and 15% (w/w) WG supplement The results showed that weight gain was significantly higher in 5% WG than that in control (p<0.05), but was not different among the WG supplement groups. Total fat weight was significantly decreased in both 10 and 15% WG supplement groups than that of control. The levels of triglycerides and free fatty acids in the plasma were significantly decreased, particularly in 15% WG supplement group (p<0.05). The levels of leptin was not significantly different among the experimental groups. Fat cell size was significantly decreased in WG supplement groups compared to that of control group (p<0.05). Correlation among the parameters demonstrated that weight gain correlated positively with total fat weight, the levels of leptin and triglycerides. Taken these results together, 15% WG supplement diet substantially reduces total fat weight, triglycerides and free fatty acids levels and fat cell size in the rat fed midium fat.